"Few people realize what an aston-
ishing achievement it is to be able to
see at all. The main contribution of
the new field of artificial intelli-
gence has been not so much to solve
these problems of information han-
dling as to show what tremendously
difficult problems they are. When
one reflects on the number of com-
putations that must have to be car-
ried out before one can recognize
even such an everyday scene as
another person crossing the street,
one is left with a feeling of amaze-
ment that such an extraordinary
series of detailed operations can be
accomplished so effortlessly in such
a short space of time."
F. H. C. Crick, "Thinking about the
Brain," in The Brain, San Francisco:
A Scientific American Book, W. H.
Freeman, 1979, p. 130.
H
ow DOES THE HUMAN BRAIN WORK? That remains the
most baffling and elusive of all questions having to do
with human understanding. Despite centuries of study and
thought and the accelerating rate of knowledge in recent years,
the brain still engenders awe and wonder at its marvelous capa-
bilities—many of which we simply take for granted.
Scientists have targeted visual perception in particular with
highly precise studies, and yet vast mysteries still exist. The most
ordinary activities are awe-inspiring. For example, in a recent
contest, people were shown a photograph of six mothers and
their six children, arranged randomly in a group. Contestants,
strangers to the photographed group, were asked to link the six
mother-and-child pairs. Forty people responded, and each had
paired all of the mothers and children correctly.
To think of the complexity of that task is to make one's head
spin. Our faces are more alike than unlike: two eyes, a nose, a
mouth, hair, and two ears, all more or less the same size and in the
same places on our heads. Telling two people apart requires fine
discriminations beyond the capability of nearly all computers, as
I mentioned in the Introduction. In this contest, participants had
to distinguish each adult from all the others and estimate, using
even finer discriminations, which child's features/head-
shape/expression best fitted with which adult. The fact that peo-
ple can accomplish this astounding feat and not realize how
astounding it is forms, I think, a measure of our underestimation
of our visual abilities.
Another extraordinary activity is drawing. As far as we know,
of all the creatures on this planet, human beings are the only ones
who draw images of things and persons in their environment.
Monkeys and elephants have been persuaded to paint and draw
and their artworks have been exhibited and sold. And, indeed,
these works do seem to have expressive content, but they are
never realistic images of the animals' perceptions. Animals do not
do still-life, landscape, or portrait drawing. So unless there is
some monkey that we don't know about out there in the forest
drawing pictures of other monkeys, we can assume that drawing
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THE NEW DRAWING ON THE RIGHT SIDE OF THE BRAIN